What happens to the ventilation rate when baroreceptors detect decreased pressure?

• A. It decreases
• B. It remains unchanged
• C. It increases
• D. It becomes irregular

Answer: (C)

When baroreceptors detect a decrease in blood pressure, the body initiates several compensatory mechanisms to restore homeostasis. One of these mechanisms is an increase in the ventilation rate.

Baroreceptors are sensory receptors located in the walls of blood vessels, primarily in the carotid arteries and aorta. They play a crucial role in regulating blood pressure by sensing changes in arterial stretch. When blood pressure falls, the baroreceptors send fewer signals to the central nervous system, specifically the medulla oblongata, which is responsible for regulating autonomic functions.

The decrease in pressure sensed by baroreceptors leads to the activation of the sympathetic nervous system. This response results in several actions: increased heart rate, increased contractility of the heart, and the stimulation of the respiratory centers in the brain, which in turn increases the ventilation rate. This increase helps enhance oxygen delivery throughout the body, particularly when perfusion may be compromised due to lowered blood pressure.

By increasing ventilation, the body can improve oxygen uptake and metabolic efficiency during states of low pressure, effectively prioritizing oxygen delivery to vital organs. Therefore, the direct relationship between decreased blood pressure and an increased ventilation rate supports the body's compensatory response to maintain sufficient oxygen levels.